1. Field of the Invention
The present invention relates to a method and an apparatus for producing toner.
2. Discussion of the Related Art
In image forming processes such as electrophotography, electrostatic recording, and electrostatic printing, electrostatic latent images are generally developed with developers. More specifically, a developer is adhered to an electrostatic latent image that is formed on an electrostatic latent image bearing member. Subsequently, the developer is transferred from the electrostatic latent image bearing member onto a transfer medium and fixed thereon. Developers are broadly classified into two-component developers comprising a carrier and a toner and one-component developers comprising no carrier and a toner (e.g., a magnetic toner, a non-magnetic toner).
Toners may be produced by what is called pulverization methods. However, pulverization methods have a disadvantage that the resulting toner particles have a wide variety of shape and size.
Recently, polymerization methods such as suspension polymerization methods, emulsion polymerization aggregation methods, dissolution suspension methods, and ester elongation polymerization methods have been proposed as methods for producing toner. Polymerization methods generally use dispersing agents in aqueous media. If dispersing agents remain on the surface of the resultant toner, chargeability and environmental stability of the toner may deteriorate. In order to remove remaining dispersing agents, disadvantageously, an extremely large amount of washing water is needed.
Additionally, spray drying methods have been also proposed as methods for producing toner recently. Spray drying methods also have a disadvantage that the resulting toner particles have a wide variety of shape and size.
Japanese Patent No. 3786034 discloses a toner production apparatus including a head part and a solidifying part. The head part discharges a raw material which has fluidity. The solidifying part solidifies the granular raw material discharged from the head part. The head part includes a raw material storage part, a piezoelectric substance that applies piezoelectric pulses to the raw material stored in the raw material storage part, and a discharge part that discharges the raw material by the piezoelectric pulses. The raw material storage part includes a vibration plate that is vibrated by vibration of the piezoelectric substance. Upon deformation of the piezoelectric substance, the vibration plate bends, thereby reducing the volume of the raw material storage part. As a result, the pressure in the raw material storage part instantaneously increases and granular raw material is discharged from the discharge part. This toner production apparatus has a disadvantage that the resultant particles have a wide size distribution, which may result in poor toner productivity. This is because only one piezoelectric substance is provided as against multiple discharge parts.